Various metals or metal alloys, for example aluminum alloys, are known for their good mechanical properties, their good thermal conductivity, their lightness and their low cost, and they have for a long time found many applications, especially for cooking utensils and vessels. However, most of these metals or metal alloys have drawbacks associated with their insufficient hardness and their insufficient wear resistance, or with their low corrosion resistance.
Attempts to obtain alloys with improved properties have been made, and these have ended in particular in quasicrystalline alloys. For example, FR-2 744 839 describes quasicrystalline alloys having the atomic composition AlaXdYeIg in which X represents at least one element chosen from B, C, P, S, Ge and Si, Y represents at least one element chosen from V, Mo, Cr, Mn, Fe, Co, Ni, Ru, Rh and Pd, I represents the inevitable smelting impurities, 0≦g≦2, 0≦d≦5, 18≦e≦29 and a+d+e+g=100%. The use of an alloy having the composition Al71Cu9Fe10Cr10 as internal coating of a Pyrex® glass cooking vessel has also been described. FR-2 671 808 describes quasicrystalline alloys having the atomic composition AlaCubCob, (B,C)cMdNeIf, in which M represents one or more elements chosen from Fe, Cr, Mn, Ru, Mo, Ni, Ru, Os, V, Mg, Zn and Pd, N represents one or more elements chosen from W, Ti, Zr, Hf, Rh, Nb, Ta, Y, Si, Ge and rare earths, and I represents the inevitable smelting impurities, with a≧50, 0≦b≦14, 0≦b′≦22, 0<b+b′≦30, 0≦c≦5, 8≦d≦30, 0≦e≦4, f≦2 and a+b+b′+c+d+e+f=100%. The alloys having the composition AlaCubCob, (B,C)cMdNeIf, with 0≦b≦5, 0<b′<22, 0<c<5, and M represents Mn+Fe+Cr or Fe+Cr, are recommended as coating for cooking utensils. According to Z. Minevski et al., [Symposium MRS, Fall 2003, “Electrocodeposited Quasi-crystalline Coatings for Non-stick, Wear Resistant Cookware”], the quasicrystalline alloys have good mechanical properties and surface characteristics that make them particularly useful for various applications, especially for the coating of cooking utensils. The alloy Al65Cu23Fe12 is cited in particular.
Although quasicrystalline alloys have in general good mechanical properties, good heat transfer properties and good impact strength and abrasion resistance, they are not, however, all useful as a coating for utensils for cooking food. In this particular application, the quasicrystalline alloy is in contact with the food, this constituting a saline medium, (owing to the addition of sodium chloride to many foods) and possibly an acid medium. It is therefore necessary for the quasicrystalline coating to exhibit good resistance to the corrosion caused by this type of medium. Now, the alloys generally recommended contain copper, which is the cause of a low corrosion resistance.